Facsimile-telegraph apparatus.



No. 759,987. PATBNTED MAY 17, 1.904. E. K. GRUHN. PAGSIMILE TELEGRAPH APPARATUS.

APPLICATION FILED "NOV. 20, 1902. no MQDEL.

' 2 SHEETS-$33111? 1.

PATENTED MAY 17, 1904.

, E.K.GRUHN.' EAGSIMILE TELEGRAPH APPARATUS.

APPLICATION FILED NOV. 20, 1902.

I0 IODIBL.

Patented ma 17, 190 1.

UNITED STATES PATENT EIcE.

ERNST KARL GRUHN, OF DRES'DEN, GERMANY, ASSIGNOR TO TELAUTO- GRAPH, GESELLSCHAFT MIT BESCHRAENKIER HAFTUNG, OF DRESDEN,

GERMANY.

FACSHVllLE-TELEGRAFH APPARATUS. l

SPECIFICATION forming part of Letters Patent No. 759,987, dated. May 17, 1904.

7 Application filed November 20, 1902. Serial No. 132,108. (No model.)

To all whom it may concern:

Be it known that I, Emvs'r KARL GRUHN, a subject of the King of Prussia, Emperor of Germany, residing at Dresden, Saxony, Em-

pire of Germany, have invented certain new and useful Improvements in or Relating to Facsimile-Telegraph Apparatus, of which the following is a specification.

The present invention relates to a sending IO or transmitting apparatus for those facsimile telegraphic apparatus in which the movements of the writing-stylus in any direction are de composed by levers connected with the stylus in components and the component motions 5 being used for varying the resistances in longdistance branch conductors, so that the variations of the resistances reconverted in the re ceiver into component motions reproduce the original writing characters or the like.

The invention is characterized by the manner in which one component motion (or both component motions) is expressed in the form of variations of the resistance (or of resistancos) by the oscillating motion of a lover (or 5 of two levers) movable with its fulcrum, and consequently of invariable length. It must be noted that the resistance to be varied is arranged on the lever as an are curved concentrically to the lever-fulcrum, so that it 3 glides upon a contadt-bar parallel to the direction of, displacement of the lever-fulcrum, and consequently is influenced. by the oscillations of the lever connected with the stylus, while the oscillations of the lever remain inoperative. This mode of utilizing the oscillations of a lever of invariable length for the purpose of decomposing the motion of the writing-stylus into orthogonal coi'irdinates distinguishes the present inventionparticu- 4 larly from a prior invention (German Patent No. 84,922) in which also an oscillating motion of a lever is used which, however, is movable relatively to a stationary fulcrum, and thus is of variable length and with which instead of orthogonal coordinates polar coordinates are described. This difference remains even if,

as in the older invention, both component mot1ons are effected by one lever owlng to the use of the displacement besides that of the oscillation. 5

In the drawings two constructions of apparatus according to this invention are shown, in one of which a special lever is used for each component motion, while one lever only is used for both component motions in the other construction, as above indicated.

Figure 1 shows the first construction in top plan View, wherein for the sake of clearness the straight guide for one of the lever-fulcra is omitted. Fig. 2 isalatoral view which for 0 the same reason only shows one system of levers. Fig. 3 is a top plan view of a second construction. Fig. 4 is a side elevation of the same. Figs. 5 and 6 are diagrammatic views illustrating modified constructions of resistance-coils.

The straight guides at a are situated in the orthogonal axis I I II II, in which are movably arranged the pivots 7) 7), as indicated. in Figs. 1 and 2. These pivots are connected, respectively, by levers c c with the writingstylus (Z, which is guided over the paper-surface at will. Mounted upon the pivots 6b are cross-barsff, which carry the resistance bodies ,r g, curved concentrically to b I). Parallel to the straight guides are contactbars it it, upon which glide the resistances g g. These resistances are, as shown in Fig.

1, insulated from each other at the crossingpoint of their arms ff and are switched into the circuit of a local battery a, while the contact-bars lb 71 are connected with the longdistance branch conductors.

When, for example, the writing-stylus (Z is moved parallel to the axisl I, this motion with 8 5 regard to the lever system situated in the axis I 1 causes a displacement of the fulcrum b, and owing to the angle of the lever relatively to the bar 71, being not varied the effect of the resistance 9 remains constant. 9

With regard to the lever system situated in the axis II II, however, the imaginary motion of the stylus has the effect of an oscillatiop of the lever c as well as of a displacement of thefulcrum Z). The latter motion also is inoperative with regard to the quantity of the resistance; but the quantity of the resistance varies according to the angular motion of the lever c. This lever, therefore, converts the component motions of the stylus effected parallel to the axis I I into variations of the resistance 9 in the same manner as the lever c converts the motion parallel to the axis II II into variations of the resistance g. In this manner the motions of the stylus decomposed into orthogonal coordinates are transmitted as variations of the electric phase of the long-distance branch conductors to the receiver. p

In the second construction (shown in top plan view in Fig. 3 and in side elevation in Fig. 4) only one lever system b 0 f is arranged with the arc-shaped resistance 9, which system gives the component motions parallel to the axis II II corresponding to the above description. In order, however, to effect the other component motions, the displacement of the lever-fulcrum b is used in a known manner. To this end the lever c is connected with a contact-arc 71;, which glides upon the resistance Z, arranged parallel to the straight guide a. The shape of the contact-arc k is selected in the manner described in another application for patent filed by me on the 21st .day of November, 1902, Serial No. 132,298,

and for the purpose of suppressing the deviaso constructed that the variation of the resistance Z is as much as possible proportionate to the componentmotion in each position of the lever system. This equalization does not, however, form the object of the present invention. An equalization, however, which refers to the function of the arc-shaped resistance body forms part of the object of the present invention. From the fact that the movement of the writing-stylus in the direction of one or other of the components is straight while the motion of the resistance over the contact-bar is circular it results that the variation of the resistance is not always precisely proportional to the movement of the point of the writingstylus. The deviations which increase with the amplitude of movement of the lever amount with an amplitude of seventeen degrees to about 1.5 per cent. As the lever without the risk of inconvenient measurements can be made so long that the imaginary angle of the amplitude is not exceeded, the slight error in practice is hardly worth consideration. Yet there are cases where great exactness and precision or a large writing-surface with a relatively short length of lever is of importance, and in these cases an equalization is desirable. This can be attained by irregularly shaping the arc-shaped resistance body in such amanner that the resistance per unit of length gradually decreases from the-center toward the ends. Then the large motion with a large amplitude is equalized by the slight increase of the resistance per unit of length of the resistant body. This can be attained in various manners. If, for instance, the resistance body consists of homogeneous substance say carbon it can from the center toward the ends gradually increase in thickness, as indicated in the construction shown in the accompanying drawings. However, if the resistance consisted of a coil the number of windings would have to be decreased toward the ends, or, in other words, the length of the wire would have to decrease per unit of length, as shown diagrammatically in Fig. 5, wherein Z indicates the coil and 2 the contacts, or the thickness of the resistance-coil could gradually increase toward the ends, as shown diagrammatically in Fig. 6, wherein V is the coil and 3/ the contacts.

I/Vhat I claim as my invention, and desire to secure by Letters Patent, is

1. A transmitting mechanism for facsimiletelegraphs embodying the following instrumentalities, whereby the movement of the stylus is decomposed into orthogonal coordinates to effect a variation in the resistance of the line conductors, to wit; a stylus, a lever connected therewith and mounted to have a bodily as well as an oscillatory movement, a resistance body whose resistance is varied by the oscillatory movements of the lever only and circuit connections; substantially as described.

2. A transmitting mechanism for facsimiletelegraphs embodying the following instrumentalities, whereby the movement of the stylus is decomposed into orthogonal coordinates to effect a variation in the resistance of the line conductors, to wit; a stylus, a lever connected therewith and mounted to have a bodily as well as an oscillatory movement, a resistance body movable in unison with the bodily movements of the lever without variation in its resistance and whose resistance is varied by the oscillatory movements of the lever, and circuit connections; substantially as described.

3. A transmitting mechanism for facsimiletelegraphs embodying the following instrumentalities, whereby the movement of the stylus is decomposed into orthogonal coordinates to effect a variation in the resistance of the line conductors, to wit; a stylus, a lever connected therewith and having a bodily movement in a right line and an oscillatory movement, a resistance body movable in unison with the lever, a contact extending in the directionof bodily movement of the lever and with which the resistance body cooperates to vary the resistance during the oscillations of the lever and circuit connections; substantially as described.

4:. In a transmitting mechanism for facsimile-telegraphs embodying the following instrumentalities, whereby the movement of the stylus is decomposed into orthogonal coordinates to effect a variation in the resistance of the line conductors, to wit; a stylus, a lever connected therewith and mounted on a fulcrum movable in a right line, an arc-shaped resistance body movable in unison with the lever, a contact extending in the direction of bodily movement of the lever and with which the arc-shaped resistance body cooperates to vary the resistance by an angular displacement of the lever and resistance-body with the fulcrum in any position of adjustment; substantially as described.

5. In a transmitting mechanism for facsimile-telegraphs embodying the following instrumentalities, whereby the movement of the stylus is decomposed into orthogonal coordinates to efl'ect a variation in the resistance of the line conductor, to wit; a stylus, a lever connected therewith and mounted to have a bodily as well as an oscillatory movement, a resistance body whose resistance is varied by the oscillatory movements of the lever only, said resistance body being so formed that the ohm resistance per unit of length decreases from the center toward the ends, and circuit connections; substantially as described.

6. In a transmitting mechanism for facsimile-telegraphs embodying the following instrumentalities, whereby the movement of the stylus is decomposed into orthogonal coordinates to efiiect a variation in the resistance of the line conductor, to wit; a stylus, a lever mounted on a fulcrum movable in a right line, an arc-shaped resistance bodymovable in uni son with the lever and so formed that the ohm movement in a right line and an oscillatory movement, an arc shaped resistance body movable in unison with the lever, an areshaped contact also movable in unison with the lever, a fixed contact extending in the line of bodily movement of the lever and with which the arc-shaped resistance cooperates, and a fixed resistance extending in the directiod of bodily movement of the lever and with which the arc-shaped contact cooperates and line connections; substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

ERNST KARL GRUHN.

Witnesses CARL Gnmnn'r, OTTO WOLFE. 

